Apparatus for determining the orientation of drill cores



Dec. 24, 1963 E. B. ROXSTROM APPARATUS FOR DETERMINING THE ORIENTATION 0F DRILL CORES 2 Sheets-Sheet 1 Filed March 24, 1960 Dec. 24, 1963 E, B, ROXSTROM' 3,115,196

APPARATUS FOR DETERMINING THE ORIENTATION OF DRILL CORES Filed March 4, 1960 2 Sheets-Sheet 2 with some parts broken away.

United States Patent 3,115,196 Patented Dec. 24 1963 Other:

APPARATUS FOR DETERMINING THE ORIENTA- TION F DRILL CORES Eric Bertil Roxstriim, Brod'dgrand 17, Hagersten, near Stockholm, Sweden Filed Mar. 24, 1960, Ser. No. 17,419 Claims priority, application Sweden Sept. 29, 1959 4 Claims. (Cl. 175-44) This invention is concerned with an apparatus for determining the orientation of drill cores taken up from boreholes, in the first place from boreholes made with diamond core drills. A determination of this core orientation is often desirable as it may indicate the slope of the rock strata encountered, in relation to the longitudinal axis of the borehole or in relation to a vertical plane.

Heretofore it has been proposed to determine the core orientation by first applying a marking to the end surface of the core facing the borehole and then taking a photograph of this marking, inside the borehole, together with a compass introduced into the hole. This procedure, however, is lengthy and tedious, since it always involves the necessity of developing the photographs before the result can be ascertained.

It is an object of this invention to eliminate the aforesaid drawback and to provide an apparatus by means of which the orientation of drill cores can be determined in a quick and simple manner. A further object is to provide an apparatus of this type which may be used in combination with already existing boring tubes.

According to an essential feature of the invention, the apparatus comprises a pin-carrier ring with a series of axial guide channels into which the pins are partially inserted, said pins being displaceable only with relatively great difiiculty or sluggishness and having their protruding ends directed to face the borehole bottom for being depressed against it, and means for indicating the orientation of the pin-carrier ring at the moment of abutting contact with the borehole bottom. In the case of inclined boreholes, these indicating means may conveniently consist of a ball in an annular chamber in which it is freely movable, said chamber being defined or bounded by a permanently deformable coating layer on the pin-carrier ring and by a pressure pad capable of being pressed against the ball and the ring. If the borehole" is a vertical hole the indicating means may conveniently be orientation marks provided on the core tubes and drill tubes employed, the pin-carrier ring being in this case movable in axial direction but incapable of being turned relatively to said tubes. 7

These and other features of the invention will now be described with reference to the accompanying drawing where FIGS. 1 and 2 are axial sectional views-of the lower portion of a borehole with inserte'd bore crown, core tube and orientation determining 'apparat us intwo different stages of operation. FIG. 1 is an axial "section of the drilling unit and FIG. 2 is an axial'sectional view In the figures, 1 is the wall of the borehole, while 2 designates the beginning :of a'core 2 that is to be taken up. The drilling unit comprises-an ordinary bore crown 3 with appertaining outer core tube 4, core-trapping 'jacket 5 and innericore tube6.

The apparatus 'for determining the orientation of the drill core consists of a pin-carrier ring 7 provided with a number of guide channels 7a into which may be inserted pins 8 which are capable of only relatively sluggish movement. The pin carrier ring 7 is movable axially on the outer surface of a substantially cylindrical central support body 9 in a pressure pad 10 outside said body and can be maintained in a desired position on the outer surface of said central support body 9by means of a locking ring or lock nut 9a. On its end facing away from the borehole bottom, the pin-carrier ring 7 is provided with a flat-surfaced, soft coating 11 in an annular chamber between said end face of the ring and the bottom of the pressure pad. Furthermore, there is a plunger 13 accommodated in a central channel in the body 9 and carrying at its end facing the drill core a pointed tip 14 and at its'opposite end a pressure plate in the form of a spring abutment 15 forming a support or battle plate for one of the ends of a helical spring 16. Just above its lower tip 14 the plunger 13 is provided with a shoulder 14a, which in operation engages the bottom of pin-carrier ring 7. Spring 16 is enclosed in a spring jacket 17 and with its other end abuts against the bottom of said jacket which in its turn is connected to the body 9 via a jacket seat 18. This jacket seat is provided, at its end remote from the spring jacket, with grooves for accommodating a number of radially directed lock bolts or locking pistons 19 which are maintained in a projecting blocking position by means of a locking cyl inder 2t) slidably mounted on the central body 9. The cylinder is axially adjustable by means of a locking ring 21 cooperating with a shoulder.v 22 on the plunger 13 in the manner as described below.- Finally, the apparatus comprises a spring detention or clutch member 23 in the form of a resilient pin attached to the central body 9 and cooperating with a groove 24 providedin the pressure plate 15 of the plunger 13.

The apparatus may be operated in the following manner: In order to make the equipment ready for use, a number of pins 8 are inserted in the pin-carrier ring 7 in such a manner that they will not reach the bottom of the guide ring with their opposite end portions. The other parts of the apparatus are assembled in that plunger 13 is inserted into the channel of the central support body 9 whereupon the pressure pad 10 is drawn or pushed onto said central body 9 to form a collar extending all around that body. A thin waterproofing or water repellent sealing layer is applied between the body 9 and the pad 10. This layer may consist of water-pump grease or the like. It will be appreciated that a similar layer should be "applied between the body 9 and the plunger 13. Then, the whole assembly is turned upside down and'theb all 12 is slid into its path on the pressure pad 11 whereupon a thin oil is poured into said ball path. Next the pin-carrier ring 7 with the inserted pins 8 is drawn onto the central body 9 so far as to leave a small play for the ball 12, e.g. of about 1 mm. As the ring approaches the pad 10 excess oil will be pressed out. When the ring has been advanced to the desired position the gap on the outside is filled with grease. Because of these oil and grease fillings, impurities are prevented from penetrating into the ball path. The pin-carrier ring is then supported in its position by screwing lock nut 9a onto the central body 9 from which the bottom portion of the pin-carrier ring is protruding.

As a next step'the locking pistons 19 are introduced and the locking ring 21. The pressure plate 15 is screwed onto the plunger 13, and the spring jacket 17 with its spring 16 is secured to the central body. Finally, compression is applied to the spring 16, this being accomplished by pressing up the plunger 13 so that it will nearly reach its uppermost position, and the spring detention pin 23 is urged into the groove 24 in the pressure plate, thus locking the plunger in its position.

When the assembly has been arranged in this manner it is inserted from above into the core-trapping jacket 5, whereupon the entire unit is slid into proper position in the inner core tube 6, so that the locking pistons will rest in recesses provided at the lower end of tube 6. Then the bore crown 3 is screwed onto the outer core tube 4, with the pins 8 and the pointed end portion 14 of the plunger 13 extending beyond the bore crown, as shown in FIG. 1.

The outer core tube 4 is then drawn tight in a manner as is commonly known for drill tube units, and is introduced into the borehole to only such depth that the pins 8 and the plunger 13 will not be pushed up by any mud that may be present on the bottom of the hole; the pin ends will then be in a position as illustrated in FIG. 1. The hole is then flushed, and during this operation the tube set is slowly advanced towards the hole bottom. When the bottom may be assumed to be mudfree the tube set is gently pressed down against the bottom, without turning or twisting. During this operation, the pins 8 will be forced up first; then, on further downward advancement of the tube set, also the plunger 13 is thrust back, and as a result thereof the pointed plunger end 14 will push the pin-carrier ring 7 upwardly on the central body 9, causing the ball 12 which rests on the lowermost part of its path to be pressed into the coating 11 by the hard pad 10. At the same time the shoulder 22 of the plunger 13 has caused an upward movement of the locking cylinder which is controlled in its position by the locking ring 21. The locking pistons 19 are thus set free and can be pressed inwardly towards the center. The spring detention pin 23 at the same time leaps out of the recess 24 in the pressure plate 15, thus allowing the compressed spring 16 to expand. Due to the spring pressure exerted on the plunger resting on the borehole bottom and the top of spring jacket 17 which is connected to jacket seat 18, the orientation determining device is pushed into the core tube so that the pins will lie completely inside the outer end portion of the bore crown (FIG. 2).

Thereafter drilling may be started in the ordinary manner. During the boring operation the growing drill core will gradually push up the orientation determining device inside the core tube. Drilling may be continued as long as there is sufiicient space for the device inside the core tube.

When the orientation determining device and the core obtained are removed from the core tube, the pins 8 which are still retained within the ring 7 in their pushedup positions are set against the uppermost end of the borehole core, i.e. against the surface of the former borehole bottom, and in this manner it is possible to determine which position the pin-carrier ring has had when the ball made its impression. A plane through the longitudinal axis of the core and of the pin-carrier ring and containing a diameter passing through the centers of the ball impression and of the pin-carrier ring will then correspond to the vertical plane through the axis of the borehole. In order that the result thus obtained be valid it is a requirement that the borehole axis deviates from the plumb line, so that an impression lying on the lowermost portion of the ball path can be obtained. Subsequent measurement with a known per se inclination indicator which shows the true inclination and direction of the borehole will then permit to determine the orientation of the stratum in which the drilling has been performed.

Since in actual practice most of the bor h les ini ia d in vertical position are rather soon apt to be deflected to one side or the other, it is nearly almost possible to use the arrangement described above. This arrangement may of course be utilized also in case of horizontal or upwardly directed boreholes. However, if the borehole is absolutely vertical it is not possible to obtain a correctly oriented ball impression; in such cases the pin-carrier ring is mounted so as to be axially displaceable but incapable of turning relatively to the drill string or tube set, and the individual tubes of the set are provided with orientation marks with the aid of which it is possible to determine the orientation of the ring at the moment of abutting contact with the borehole bottom.

What I claim is:

1. Apparatus for determining the orientation of drill cores taken up from boreholes, comprising a core tube for accommodating a core taken up, a substantially cylindrical support, a pin-carrier ring which is mounted slidably in the axial direction on the outer surface of said support, said pin-carrier ring being formed with a series of axial guide channel pins partially insented in said channels in which they are capable of only relatively sluggish movement, the ends of said pins when depressed against the borehole bottom being adapted to be pushed further back into said channels so as to depict the contour of the core surface, said apparatus comprising furthermore a locking mechanism holding said pin-carrier ring support in releasable locking engagement in the core tube, a central plunger mounted inside said hollow support and having a shoulder extending beneath said pin carrier for engagement thereagainst and having an end portion adapted to contact the borehole bottom thereby to cause upward sliding movement of said ring on said support, and means indicating how the pin-carrier ring has been oriented at the moment of abutting contact of said pin ends against the borehole bottom.

2. Apparatus according to claim 1, in which said plunger is provided with a second shoulder, said locking mechanism comprising radially directed locking pistons which are mounted slidably on said support to lock with said core tube, a locking cylinder means maintaining said pistons in outwardly projecting locking positions and releasing said pistons from said projecting locking positions to perform a movement rtowards the center when said locking cylinder means is displaced by being engaged by said second shoulder on said plunger.

3; Apparatus according to claim 1, in which said plunger is provided with a second shoulder, said locking mechanism comprising radially :directed locking pistons which are mounted slidably on said support to lock with said core tube, a locking cylinder means maintaining said pistons in outwardly projecting locking positions, and releasing said pistons from said projecting locking positions, to perform a movement towards the center when said locking cylinder means is displaced by being engaged by said second shoulder of said plunger, a spring jacket having an end serving as a spring abutment and being connected with said pin ring and said support, an abutment connected with said plunger, a spring being provided between said abutments under load biasing said jacket inwardly to cause said pin-carrier ring and support to move away from the drill core in the core tube when said lock-pistons are released by upward movement of said locking cylinder.

4. Apparatus according to claim 1 in which said plunger is provided with a second shoulder, said locking mechanism comprising radially directed locking pistons which are mounted slidably on said support to lock with said core tube, a locking cylinder means maintaining said pistons in outwardly projecting locking positions, and releasing said pistons from said projecting locking positions to perform a movement towards the center when said locking cylinder is displaced upwardly, said cylinder having abutment means located in the path of said second shoulder when said plunger moves upwardly whereby said upward cylinder is pressed upwardly by said second shoulder of said plunger, a pressure plate on said plunger, 9. spring jacket connected with said support and having a spring abutment, a spring in compressed state located between said pressure plate and said spring abutment of said spring jacket to cause said pin-carrier ring and support to move away from the drill core in the core tube when said locking pistons are released.

References Cited in the file of this patent UNlTED STATES PATENTS Kimball Feb. 5, 1889 Baker Feb. 24, 1931 Sweet et al. Apr. 16, 1940 Moore Apr. 5, 1949 Natland et a1. June 10, 1952 

1. APPARATUS FOR DETERMINING THE ORIENTATION OF DRILL CORES TAKEN UP FROM BOREHOLES, COMPRISING A CORE TUBE FOR ACCOMMODATING A CORE TAKEN UP, A SUBSTANTIALLY CYLINDRICAL SUPPORT, A PIN-CARRIER RING WHICH IS MOUNTED SLIDABLY IN THE AXIAL DIRECTION ON THE OUTER SURFACE OF SAID SUPPORT, SAID PIN-CARRIER RING BEING FORMED WITH A SERIES OF AXIAL GUIDE CHANNEL PINS PARTIALLY INSERTED IN SAID CHANNELS IN WHICH THEY ARE CAPABLE OF ONLY RELATIVELY SLUGGISH MOVEMENT, THE ENDS OF SAID PINS WHEN DEPRESSED AGAINST THE BOREHOLE BOTTOM BEING ADAPTED TO BE PUSHED FURTHER BACK INTO SAID CHANNELS SO AS TO DEPICT THE CONTOUR OF THE CORE SURFACE, SAID APPARATUS COMPRISING FUR- 